{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2021-47300", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2021-47300", "idYear": 2021, "status": "PUBLISHED", "publishedAt": "2024-05-21T14:35:22.040Z", "updatedAt": "2026-08-05T08:47:09.253Z", "importedAt": "2026-10-24T01:56:36.661Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "bpf: Fix tail_call_reachable rejection for interpreter when jit failed", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix tail_call_reachable rejection for interpreter when jit failed\n\nDuring testing of f263a81451c1 (\"bpf: Track subprog poke descriptors correctly\nand fix use-after-free\") under various failure conditions, for example, when\njit_subprogs() fails and tries to clean up the program to be run under the\ninterpreter, we ran into the following freeze:\n\n [...]\n #127/8 tailcall_bpf2bpf_3:FAIL\n [...]\n [ 92.041251] BUG: KASAN: slab-out-of-bounds in ___bpf_prog_run+0x1b9d/0x2e20\n [ 92.042408] Read of size 8 at addr ffff88800da67f68 by task test_progs/682\n [ 92.043707]\n [ 92.044030] CPU: 1 PID: 682 Comm: test_progs Tainted: G O 5.13.0-53301-ge6c08cb33a30-dirty #87\n [ 92.045542] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/2014\n [ 92.046785] Call Trace:\n [ 92.047171] ? __bpf_prog_run_args64+0xc0/0xc0\n [ 92.047773] ? __bpf_prog_run_args32+0x8b/0xb0\n [ 92.048389] ? __bpf_prog_run_args64+0xc0/0xc0\n [ 92.049019] ? ktime_get+0x117/0x130\n [...] // few hundred [similar] lines more\n [ 92.659025] ? ktime_get+0x117/0x130\n [ 92.659845] ? __bpf_prog_run_args64+0xc0/0xc0\n [ 92.660738] ? __bpf_prog_run_args32+0x8b/0xb0\n [ 92.661528] ? __bpf_prog_run_args64+0xc0/0xc0\n [ 92.662378] ? print_usage_bug+0x50/0x50\n [ 92.663221] ? print_usage_bug+0x50/0x50\n [ 92.664077] ? bpf_ksym_find+0x9c/0xe0\n [ 92.664887] ? ktime_get+0x117/0x130\n [ 92.665624] ? kernel_text_address+0xf5/0x100\n [ 92.666529] ? __kernel_text_address+0xe/0x30\n [ 92.667725] ? unwind_get_return_address+0x2f/0x50\n [ 92.668854] ? ___bpf_prog_run+0x15d4/0x2e20\n [ 92.670185] ? ktime_get+0x117/0x130\n [ 92.671130] ? __bpf_prog_run_args64+0xc0/0xc0\n [ 92.672020] ? __bpf_prog_run_args32+0x8b/0xb0\n [ 92.672860] ? __bpf_prog_run_args64+0xc0/0xc0\n [ 92.675159] ? ktime_get+0x117/0x130\n [ 92.677074] ? lock_is_held_type+0xd5/0x130\n [ 92.678662] ? ___bpf_prog_run+0x15d4/0x2e20\n [ 92.680046] ? ktime_get+0x117/0x130\n [ 92.681285] ? __bpf_prog_run32+0x6b/0x90\n [ 92.682601] ? __bpf_prog_run64+0x90/0x90\n [ 92.683636] ? lock_downgrade+0x370/0x370\n [ 92.684647] ? mark_held_locks+0x44/0x90\n [ 92.685652] ? ktime_get+0x117/0x130\n [ 92.686752] ? lockdep_hardirqs_on+0x79/0x100\n [ 92.688004] ? ktime_get+0x117/0x130\n [ 92.688573] ? __cant_migrate+0x2b/0x80\n [ 92.689192] ? bpf_test_run+0x2f4/0x510\n [ 92.689869] ? bpf_test_timer_continue+0x1c0/0x1c0\n [ 92.690856] ? rcu_read_lock_bh_held+0x90/0x90\n [ 92.691506] ? __kasan_slab_alloc+0x61/0x80\n [ 92.692128] ? eth_type_trans+0x128/0x240\n [ 92.692737] ? __build_skb+0x46/0x50\n [ 92.693252] ? bpf_prog_test_run_skb+0x65e/0xc50\n [ 92.693954] ? bpf_prog_test_run_raw_tp+0x2d0/0x2d0\n [ 92.694639] ? __fget_light+0xa1/0x100\n [ 92.695162] ? bpf_prog_inc+0x23/0x30\n [ 92.695685] ? __sys_bpf+0xb40/0x2c80\n [ 92.696324] ? bpf_link_get_from_fd+0x90/0x90\n [ 92.697150] ? mark_held_locks+0x24/0x90\n [ 92.698007] ? lockdep_hardirqs_on_prepare+0x124/0x220\n [ 92.699045] ? finish_task_switch+0xe6/0x370\n [ 92.700072] ? lockdep_hardirqs_on+0x79/0x100\n [ 92.701233] ? finish_task_switch+0x11d/0x370\n [ 92.702264] ? __switch_to+0x2c0/0x740\n [ 92.703148] ? mark_held_locks+0x24/0x90\n [ 92.704155] ? __x64_sys_bpf+0x45/0x50\n [ 92.705146] ? do_syscall_64+0x35/0x80\n [ 92.706953] ? entry_SYSCALL_64_after_hwframe+0x44/0xae\n [...]\n\nTurns out that the program rejection from e411901c0b77 (\"bpf: allow for tailcalls\nin BPF subprograms for x64 JIT\") is buggy since env->prog->aux->tail_call_reachable\nis never true. Commit ebf7d1f508a7 (\"bpf, x64: rework pro/epilogue and tailcall\nhandling in JIT\") added a tracker into check_max_stack_depth() which propagates\nthe tail_call_reachable condition throughout the subprograms. This info is then\nassigned to the subprogram's \n---truncated---", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "ebf7d1f508a73871acf3b2bfbfa1323a477acdb3", "status": "affected", "versionType": "git", "lessThan": "39f1735c8107ef43a53c4daf82f330d880488d8f" }, { "version": "ebf7d1f508a73871acf3b2bfbfa1323a477acdb3", "status": "affected", "versionType": "git", "lessThan": "cbb086074dab631ac43f8645cbac1d7b148e05c4" }, { "version": "ebf7d1f508a73871acf3b2bfbfa1323a477acdb3", "status": "affected", "versionType": "git", "lessThan": "5dd0a6b8582ffbfa88351949d50eccd5b6694ade" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "5.10", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "5.10" }, { "version": "5.10.54", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.13.6", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.13.*" }, { "version": "5.14", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }